Chisel for slate-splitting machines



Nov. 4, 1952 E. T. LAKE CHISEL FOR SLATE-SPLITTING MACHINES Filed Jan. 12, 1950 INVENTOR EUGENE T. LAKE BY HIS ATTORNEYS Patented Nov. 4, 1952 UNITED ,s TATE'S FPATi-ENT o F 101E CHISEL "FO'R SLATE- SPLITTlNGi M'AGHINE'S n T- Lak liiidhcadsville la.

.Applicationflanuary 12, 1950,SeriaI NOEISSJS'I (c amsss) 4 Qlaims.

.ilzhiszinventicn a-eiates {toe-at chisel sfonazslate- :spl itin machine.

for-many.zcentwtiessslate,:.after :being. removed :imm he; quarry. "-mai i phtjnti)II-1111 351186135iby a wa te :Of 1, 5 9%; as "Well; asibein 1. v Machin s .';for splitting wzslate installermigre bee kn maestorexamole, that shown; initheU-i t atent toWinc.ent:F. -Lake, No. vlzfi9.9:3fi5.iia ed :J 29; 1926. that machine, a chisel blade is reciprocated -veryqrapidly {by mechanical means a ainst the '2 slate along :the i-gaturaljlines ofqcleavageioithe slate. These-maiohil fisi-ushdwhiseis zfilwh .--as shown .iniig. ll of the;patent,v or bl-ade s;such as shown in-the Vin- .oent F.- Lake p t n Nc...l;- 9- 22; dated une :12, 1.9197. These were i-broad blades composed :of'l plurality offlexible; portions e0 planar but spaced short distances ,from each other. 'It =W3JS found that individual portions or -fingers of the blade .spacedgshoizt distances apart were somewhat'iun- ,,-sa tisfact01? rinthat :sli-vers could ;:get between "them. The object ;of my invention 1' is rto provide an improved form of chisel for such ;machines, .in whichithe chances qof slate being caught between the individual-fingers of the blade arexre- .duced=to a minimum, and the abilityzof :the chisel to -,work the slivers but of itself is greatly improved. :My {invention :is characterized by -.the Jaet that the edge of the ichisel {blade :is sheared or split f1'. .mi,a';.1ng1e piece of, :material avithout the iremovalof gany metal, except :as necessary :to -S; .1 QQth iOfi bln'lis or :fins :pro duced by 'athe shearing. ,In :this waythe-individua1 fingers :are :in

.;fu il;con;tact with .Qachaother at the cutting edge :hl .zfQ 55.0. 118 tdistancelback :from it. Back of illescuttingsedge :a longitudinal :extension is "made :Qf reach :such gshear'ing :line' in the :form -:of a slot .zfdllmed by goutting 01.11, :metal. Z'Ilhese slots are considerably ilonger than they are wide. It is found that byrnot iremovi-ng any metal-for some distance .back from the cutting edge, the chances of slivers getting between the individual portions or fingers of the bladeare minimized, and that if the slivers do get :in :they gradually workzthemselves back to the open slots. .Thfl'1510175 vbeing longer than they are thick, the slivers will drop out.

In the drawings,

Figure '1 is an edge view of a slate-Splitting chisel made in --accorda-nce with my invention;

"Figure"? is a view of the chisel of Fig.=--l on its width;

Figure 3 is a cross-section of the lower edge of the chisel taken on the line 33 of Fig. 2, show- -ing thezreduced edge WhiGh,1TYCfiIIg in a groove,

:serves torguid'enthe chisel abla'de inits reciproca- -:tionywwhile :Figure .4: isiaadiagramiof the-shape of the ciit- 'tin-gzed'geJif ithe chisel,i.taken on the same p'lane rand-escalates ":adja'centxFigure 1, except :that the -:'.thickness fifxtheibladeiis multiplied in orderthat :the angles :of lithe :wedge :and: flanks can bo-seen diagrammatically. :rlVIy slate-splitting .chisel :is

amounted and operated inza mannersimilanto the ;,ohise1 :shown iin :the Lake patent, :No. -lj590",3 85,

"sabove-smentioned. The iblade .is shown placed with its width in a vertical dimension, but it 51811011 111 be :understood'ithat lit cantbe use'd inany .;other :desired idimension. In machines of this -genera1?type, theichiselisigadapted to give many ithousands of :blows perrminute to the-slate. No single aibl'ow Li's cas strong a the single blow .o-f a hand :splitter, [the :desired result being obtained abecause of -the grea'ter'number o'f blows'applied.

-With .suchqa typefof action, I it isnecessary that .the'edgebf the'chi'sel be broken at'a number of "3110111135 particularly when splitting "thin slate.

This enables the resulting independent portio'ns :o-f .the chiselxto follow t-any local variations in .acleavage planes in'ithe s'late, which avoids breakagetof the slate. =A-ssindicated above, experience .:with -.-suoh'1machines shows that relatively dong slivers of islate :tend to become wedged between the blades, :destroying their flexibility "holding a ifinger :out -.of line with :its neighbors and making zitmeeessary to shutdown-the machineifor cleanting.

My chisel-rbla'detl is mounted on a socket bar or shank 2,:at Tthe .116941 end of which is a :roller adapted :to receive :th'e imoacts from the operating ream ,(notsshoWn). "The blade is mounted ron-theishank by'zmearrs o fri'v'ets 4, "there being a washer 5 at therear end of the blade I to prowide a shoulder for :a spring (not shown) Inter- --mediate the wa'sh'er and th'e roller is a regulating notch fi ha'v'ing fimpaht' edges '1 cooperating with v a regulatingslide knot shown) to adjust the-blows -"a little shortof' the'lengthbf the slots shown. It

tapers down' f-romthis width at that point to the width of the shank which --carri'e's it. 'The' taper is indioated by the reference character M. The

cutting edge of the blade is in the shape of a symmetrical wedge 9. This wedge is of a higher angle than the flank ID. This has been found a desira'ble form of chisel for splitting slate (see Fig. 4). As explained in the Lake patent, No. 1,229,- 622, above-mentioned, in order to enable the blade to follow any local variations in the planes of the slate, each finger 8 of the cutting edge of the blade must be free to move slightly out of line of the neighborin fingers. In accordance with the two Lake patents mentioned above, slot-s were sawn at spaced points along the cutting edge, straight back. Instead of removing metal from the cutting edge, I propose to shear or split the blade at spaced points along the cutting edge. These splits or shearing lines are indicated in the drawings by the reference character ll. As shown, these shearing lines extend past the wedge 9 well into the flanks H) of the blade. By not removing any metal from the cutting edge but merely shearing the metal, the chance of splinters of slate getting in between the individual fingers 8 of the cutting edge is minimized. Experience shows that occasionally, even under these conditions, slivers will get in between the fingers of the blade. Such slivers, of course, are very thin and are many times as wide as they are thick. I have discovered that such slivers as get into the sheared lines of my new blade can be removed by providing an actual slot l2 back of each sheared line, in extension thereof. Of course, metal has to be removed to form the slot. These slots are long enough to enable the entire sliver to work out of the sheared line and free itself into the slot where the metal has been removed.

As shown in Fig. 2 of the drawings, the shank end of the blade has a tapered form narrowing the blade down to approximately the size of the socket. It is known that with such a taper the outside fingers 8 at the top and bottom are slightly more flexible than the neighboring fingers between them. This is desir-able because the slate at the edges of the block is generally not as strong as at the center of the block. This weakness of the outside fingers, however, is uneven because the taper comes from only one side. To make this weakness of the outside fingers more even and prevent twisting with the resultant risk of damage to the slate, I have extended the slots into the tapered portion. It will be noticed that these slots l l are at least as long as the sheared lines in a new blade. I find that cutting metal out for a width of 1% of an inch is sufficient to enable any slivers that get caught in the sheared lines to Work themselves free and drop out in the open slots. Since clogging by splinters can jam the machine or cause breakage of the blade, it is therefore necessary, in case of clogging, to stop the machine and clear it at once. It will be obvious that my provision of sheared lines rather than open slots is a great practical improvement and that backing up these sheared lines with open slots to enable the machine to clear itself automatically is a still further improvement. The use of a slot back of the sheared lines which is at least equal to the length of the Wedge will enable practically all slivers to free themselves. I prefer the longer slots shown.

This invention of the sheared lines in the blade is peculiarly. useful in splitting thin slate where the danger of a sliver breaking the slate is great. .I find that when dealing with a relatively thick block of slate, not only does the chisel have to go in a lesser distance before the splitting occurs but the slate will be strong enough to crush a sliver instead of being broken by the sliver. It is, therefore, possible, when splitting relatively thick slate, to use one of my new blades which has been worn down in splitting thin slate until the cutting edge has reached the open slots 12.

As in the case of the prior Lake patents, I prefer to guide the lower edge of the chisel blade in a groove to which the bottom edge l3 of reduced thickness (see Fig. 3) fits in but slides freely.

Where in the claims I speak of split lines in making the chisel, it should be understood that I refer to dividing lines, whether produced by shearing or otherwise splitting the metal.

What I claim is:

l. A chisel for a power-driven slate splitting machine comprising a blade of resilient material having a wedge for a cutting edge, the blade maintaining its maximum width for a substantial distance back of the cutting edge and then tapering toward the opposite end of the blade, said blade being divided along a plurality of spaced lengthwise lines throughout at least substantially its maximum width into a plurality of fingers by split edges in contact with each other at the cuttin edge of the chisel and for some distance back of the wedge, in combination with narrow elongated slots forming linear extensions of the split edges, the length of each slot being at least of the order of the length of its split: for

the purposes described.

2. A chisel for a slate-splitting machine according to claim 1 in which there is a shank on which the blade is mounted, the blade being tapered in width at the shank end, the slots in the blade extending as far as but not beyond the first part of the tapered portion of the blade, whereby any tendency of the outside fingers of the cutting edge to twist is minimized.

3. A chisel for a slate-splitting machine according to claim 1 in which each slot is cut of uniform width for a distance equal substantially to the length of the sheared line of which it is an extension.

4. A chisel for a newer-driven slate splitting machine comprising a, blade of resilient material having a wedge for a cutting edge, the blade maintaining its maximum width for a substantial distance back of the cuttin edge and then tapering toward the opposite end of the blade, said blade being divided along a, plurality of spaced lengthwise lines throughout at least substantially its maximum width into a plurality of fingers by split edges in contact with each other at the cutting edge of the chisel and for some distance back of the wedge, in combination with narrow elongated slots forming linear extensions of the split edges, the length of each slot being sufiicient to enable the edges of the split to deflect out of the plane of the chisel till clear of each other without permanent deflection.

EUGENE T. LAKE.

REFERENCES CITEB The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,229,622 Lake June 12, 1917 1,590,385 Lake June 29, 1926 1.654.770 Williams Jan. 3, 1928 

